This invention relates to novel tris(aryl)alkyl phosphonium compounds and to the use of these compounds as bacteriocides and non-phytotoxic fungicides.
The prior art teaches that many quaternary phosphonium compounds exhibit useful levels of insecticidal, fungicidal and bacteriocidal activity. Specific patents relating to this subject include U.S. Pat. Nos. 3,230,068; 2,946,824; 2,418,652 and 3,445,570. Unfortunately many of the phosphonium compounds disclosed in the prior art, particularly tri(phenyl)alkyl phosphonium halides, are moderately to severely phytotoxic when employed at the minimum concentration level required to control fungi such as bean mildew on a living plant. These compounds therefore cannot be used as agricultural pesticides.
It has now been found that the phytotoxicity of tri(phenyl)alkyl phosphonium compounds can be reduced to a non-detremental level or eliminated entirely without significantly affecting fungicidal and bacteriocidal activity if certain substituents are present on the phenyl groups.